Three people have reportedly been killed in an anti-terrorism raid in Verviers, BelgiumGoogle Maps

Three people have reportedly been killed and explosions have been heard after police in Belgium launched a raid against a suspected terrorist group in the city of Verviers, near Liège.

Anti-terrorism police carried out an operation against a suspected Islamist cell in the city centre, at the top of the rue des Ecole at around 6pm local time (1700 GMT), local media reported.

Eyewitnesses reported hearing several detonations and seeing black-clad men fleeing the scene.

"I was in my car in front of the courthouse and I heard two explosions," a witness told Le Soir newspaper.

"I saw two young men, aged 25 to 30, of northern African origins dressed all in black and with a bag of the same colour hurtling," the witness said, adding that moments later the whole area was blocked by police.

Early reports said two suspects were killed and one arrested, while others said three people had died.

Gunfire can be heard and flames seen in a video purportedly showing the incident uploaded online.

"Thanks to this operation a Charlie Hebdo has been avoided in Belgium," a police source told Sudpresse, referring to the French satirical magazine targeted in a deadly Islamist attack in Paris on 7 January.

The Verviers suspects had recently returned from fighting in Syria, according to La Libre newspaper.

Police was reportedly carrying out raids and searches as part of the same anti-terrorism operation also in the capital, Brussel, and in Molenbeek.

Federal prosecutors will hold an emergency news conference later this evening (15 January).

It is not the first time Belgium is linked to Islamic extremism. Earlier this week, a notorious figure from the Brussels underworld accused of supplying weapons to the French brothers who carried out the Charlie Hebdo massacre handed himself over to police.

Last year, Mehdi Nemmouche, a French jihadist who fought in Syria, shot dead four people at the Brussels Jewish Museum.